JP2000086205A - Ozonizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a small-size pulse power type ozonizer. SOLUTION: In the ozonizer, a pressure tank 8 having an inlet 17 to introduce source gas and a discharge port 18 to discharge ozone is provided with a ground electrode 10 and a high voltage electrode 13. By controlling the pressure in the pressure tank 8, for example, to 5 atm. absolute pressure, the inner diameter D of the ground electrode 10 can be decreased from 60 mm for an inner pressure of 1 atm to 10 mm, thus making the pressure tank 8 smaller in size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone generator, which is a miniaturized ozone generator.

[0002]

2. Description of the Related Art Since ozone has an extremely strong oxidizing power, it is used for sterilization, deodorization, or decolorization. For this reason, ozone is used for water and sewage treatment and human waste treatment. In this case, since a high concentration and a large amount of ozone are required, the ozone is generally generated by a silent discharge method.

[0003] The principle of ozone generation by the silent discharge method is as follows.
This is for generating ozone electrochemically from air or oxygen as a raw material gas. As shown in FIG. 3, a pair of dielectrics 1 is provided through a gap, and a high voltage electrode 2 fixed to each dielectric 1 is provided. And an AC or high frequency high voltage power supply 3 is connected to the power supply.

[0004] However, the silent discharge method has a low ozone generation efficiency, and raises the cost of the generated ozone. In other words, the power required to obtain ozone per unit volume is
Of theory that is 1.2kWh / kg-O _3, reality is required to be about 14kWh / kg-O _3, only a few percent of the power consumption is used to generate ozone, Most is consumed as waste heat. Since the efficiency of ozone generation greatly depends on discharge energy, discharge shape, temperature, and pressure, (1) electrode and dielectric shapes (2) applied voltage and frequency (3) improvement to optimize cooling of reaction space This has been done conventionally. However, no dramatic improvement in discharge power consumption is observed.

For this reason, a pulse power type ozone generator shown in FIG. 4 has been proposed. In this configuration, a high voltage side electrode 5 is disposed at an axial center of a cylindrical grounding side electrode 4, and a pulse power source 6 is connected between both electrodes. here,
Both ends of the high voltage side electrode 5 are supported via a pair of insulating plates (not shown) arranged near both ends of the ground side electrode 4. The pulse power supply 6 supplies a pulse having a steep rise and a short duration between both electrodes. When such an impulse is supplied, a uniform non-equilibrium plasma discharge is performed inside the ground electrode 4 which is a discharge space. For this reason,
When the source gas is supplied from the left side of the ground side electrode 4, the ozone gas is discharged from the right side.

In order to obtain industrially required high-concentration ozone, it is necessary to increase the production of ozone and at the same time reduce the decomposition to raise the ozone concentration in the equilibrium state. In order to generate ozone, it is necessary to dissociate oxygen molecules to generate O atoms as a first reaction, and first, electrons having sufficient energy are required. Subsequently, a reaction for generating ozone from O atoms and a reaction for decomposing the generated ozone again proceed at the same time. Which reaction is inclined depends on the temperature. The lower the temperature, the lower the gas temperature because the chemical equilibrium is inclined toward the generation side and high concentration ozone can be generated.

[0007] Non-equilibrium plasma satisfies such a low gas temperature condition. In non-equilibrium plasma, only electrons with a small mass gain high energy from the electric field and the electron temperature rises. However, molecules and ions cannot keep up with rapid changes in the electric field, so that the low-energy gas temperature is low. Therefore, by using non-equilibrium plasma,
Ozone can be generated efficiently.

The silent discharge method also uses non-equilibrium plasma. However, since the silent discharge is a collection of minute streamer discharges, the electron density is not uniform. Therefore, in the spot where energy is injected, the electron density necessary for generation of O atoms is concentrated, but at the same time, since the gas temperature is also high in a spot-like manner, the chemical equilibrium is hardly inclined to ozone generation. Therefore, the ozone generation efficiency does not improve as a whole.

On the other hand, since the discharge using the pulse power method occurs uniformly in the reaction space and there is no spot having a high gas temperature, the characteristics of the non-equilibrium plasma can be effectively used. Therefore, power consumption can be reduced.

[0010]

However, since the pulse power type ozone generator utilizes corona discharge, a gap larger than a certain level is inevitably required, and compared with the silent discharge type ozone generator. As a result, the ozone generator itself becomes large because the discharge gap is large.

On the other hand, if the discharge gap is simply reduced, the glow-shaped corona discharge shifts to arc discharge, and ozone is not effectively generated. That is, miniaturization cannot be achieved.

[0012] Therefore, an object of the present invention is to provide an ozone generator which solves such a problem.

[0013]

According to a first aspect of the present invention, there is provided an ozone generator, wherein a high-pressure side electrode is disposed at an axial center of a cylindrical grounding-side electrode, and a pulse width of the ozone generator is reduced. In an ozone generator configured to apply a short and steep rising high voltage pulse between the two electrodes at a high repetition rate and to feed a raw material gas into the ground electrode, the pressure inside the ground electrode is reduced. Is set to be greater than 1 atm absolute pressure and not more than 10 atm pressure.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ozone generator according to the present invention will be described below.

(A) First Embodiment As shown in FIG. 1, the vicinity of both ends of a cylindrical ground-side electrode 10 is supported inside a pressure vessel 8 also serving as an electromagnetic shield via a pair of support plates 9a and 9b. ing. This ground electrode 1
The inner diameter D of 0 is 10 mm. Outside each of the pair of support plates 9a, 9b, an insulating plate 11a, 1
1b are attached to each other substantially in parallel via a plurality of insulating support rods 12. And the ground electrode 10
Both ends of a rod-shaped high-voltage electrode 13 disposed at the axial center position are supported by a pair of insulating plates 11a and 11b.

A current terminal 15 is provided through the pressure vessel 8 in an airtight manner. The high-voltage side electrode 13 is connected to the current terminal 15 via a cable 14.
To a pulse power supply (not shown). An inlet 17 for introducing a raw material gas is formed at an upper portion on one end of the pressure vessel 8, and an outlet 18 for discharging ozone gas is formed at an upper portion on the other side. In addition, cooling water 19 circulates and flows in a portion surrounded by the pair of support plates 9a and 9b.

Next, the operation of the ozone generator will be described. The internal pressure of the inside of the pressure vessel 8 other than the portion filled with the cooling water 19 is set to 5 atm in the present embodiment in which the absolute pressure is more than 1 atm and 10 atm or less. Even in this state, the pressure vessel 8, the ground-side electrode 10, and the current terminal 15 have a pressure-resistant structure so as to withstand sufficiently.

As described above, the internal pressure of the pressure vessel 8 is increased from 1 atm to 5 atm, and a high-voltage pulse having a short pulse width and a sharp rise is supplied at a high repetition rate while supplying a raw material gas from the inlet 17. When applied between the ground side electrode 10 and the high voltage side electrode 13, D = 10 mm (conventionally, D =
Even if the discharge gap between the ground side electrode 10 and the high voltage side electrode 13 is as small as about 1/5 of the conventional one, corona discharge is stably performed. Generation of ozone from the gas is performed smoothly.

(B) Second Embodiment Next, a second embodiment will be described. Embodiment 2 is shown in FIG.
And the high voltage side electrode 13 which were single in
And a plurality of combinations are provided to form a multi-tube structure.

The other configuration and operation are the same as those of the first embodiment, and the description is omitted.

The shape of the high-voltage side electrode can be set arbitrarily. For example, it is possible to make the outer diameter 5 mm and make it hollow.

[0022]

As can be seen from the above description, claim 1
According to the ozone generator according to the above, since the pressure inside the ground electrode is set to a range of more than 1 atm absolute pressure and 10 atm or less, the glow-shaped corona discharge is not transferred to the arc discharge, so By making the inner diameter of the electrode smaller than before, the ozone generator can be downsized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing Embodiment 1 of an ozone generator according to the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the ozone generator according to the present invention.

FIG. 3 is a configuration diagram of a conventional silent discharge type ozone generator.

FIG. 4 is a configuration diagram of a conventional pulse power type ozone generator.

[Explanation of symbols]

 8 pressure vessel 10 ground electrode 13 high pressure electrode

Claims (1)

[Claims] 1. A high voltage side electrode is arranged at the axial center of a cylindrical grounding side electrode, and a high voltage pulse having a short pulse width and a sharp rise is applied between the two electrodes at a high repetition rate and grounding. An ozone generator configured to feed a raw material gas into the side electrode, wherein the pressure inside the ground electrode is set to be greater than 1 atm absolute and not more than 10 atm.